El Nino yet to register on rain buckets
SFL Weekly Watersheds Summary: Nov 27 – Dec 3
RAINFALL. There’s been talk of El Nino amplifying our dry season rainfall totals this winter, but so far this dry season our rain buckets have been largely dry. The ENSO index is currently at a similar El Nino range as in 2003 and 2005, and both those year’s were normal to below normal dry season rainfall in south Florida. Going back in time, the multivariate ENSO index spiked to over twice this year’s current level in 1998, 1995, 1987, and 1983 (with the lofty index readings in 1983 and 1998 prompting scientists to dub them as “El Ninos of the century”). During those years, dry season rainfall totals (Nov through May) ran up into the 20 inch range, or more than twice the usual dry season total of 12 inches for the Big Cypress. So far this year, Big Cypress National Preserve received 1.5 inches for November, which is 0.8 inches below our 2.3 inch average for November, … and which seems all the drier considering that we had such a dry October (0.8 inches).
BIG CYPRESS. Preserve-wide wetland water levels have been tracking at their 5-year low for the past 7 weeks (since the middle of October). Incredibly, it was only 4 weeks prior in the middle of September that wetland water levels were tracking at their 5-year high following Ernesto. The swamps filled to the top of the brim this year, but it was a short-lived “full cup”. The wetting front has dropped below the wet prairies and retreated into the tall cypress, marshes, and swamp forested — but some prairies still are holding on with a inch or two of water, or a spongy marl bottom at the least. Look for wildlife to similarly retreat into the low-water refugia, and/or start hanging out more at the canals and borrow pits as water levels continue to fall.
EVERGLADES. Flows through the S12s are coming to a close. For the past 3 years, over 1500 cfs was still flowing through the S12s at the start of December, but this year is more similar to 2002 and 2000 when S12 flows came to an early end by the start of December. Water depths in southern 3A are currently tracking at a 2.6 ft depth. That’s about 10 inches lower than December of last year, and the shallowest that water depths in southern 3A have been in December since 2000. Water is currently pooling over 3 ft behind the S10s, just over 2 ft behind the S11s, and around 1.8 ft behind the S12s.
LAKE O. Its been a quiet summer for the lake. Other than Ernesto’s ~1.5 ft boost to lake stage, touching up at its highest point to the bottom of the Lake’s interior littoral zone, inflows and outflows to the Lake have been almost non-existent this summer in comparison to recent summers. In comparison to just a year ago in December of 2005, the S79 was still flowing then at over 5000 cfs in attempt to draw lake stage down from its greater than 3 ft ascent above the bottom of the littoral zone in the wake of Wilma. In its entirety, S79 flowed at 5,000 cfs or above for over 5 months last year in comparison to only exceeding 5000 cfs for about 2 weeks this year. The Lake is currently at about the exact same stage at it was from June to August of this year before >10 inches fell in the S79 basin in early September. Don’t forget that Ernesto’s 15,000 cfs spike through the S79 wasn’t from the Lake … it was all local watershed flow from the S79 basin, which is also a big difference from last year.